/*++

Copyright (c) 2006, Intel Corporation                                                         
All rights reserved. This program and the accompanying materials                          
are licensed and made available under the terms and conditions of the BSD License         
which accompanies this distribution.  The full text of the license may be found at        
http://opensource.org/licenses/bsd-license.php                                            
                                                                                          
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,                     
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. 

Module Name:

  Udp4Main.c

Abstract:

--*/

#include "Udp4Impl.h"

EFI_UDP4_PROTOCOL  mUdp4Protocol = {
  Udp4GetModeData,
  Udp4Configure,
  Udp4Groups,
  Udp4Routes,
  Udp4Transmit,
  Udp4Receive,
  Udp4Cancel,
  Udp4Poll
};

EFI_STATUS
EFIAPI
Udp4GetModeData (
  IN  EFI_UDP4_PROTOCOL                *This,
  OUT EFI_UDP4_CONFIG_DATA             *Udp4ConfigData OPTIONAL,
  OUT EFI_IP4_MODE_DATA                *Ip4ModeData    OPTIONAL,
  OUT EFI_MANAGED_NETWORK_CONFIG_DATA  *MnpConfigData  OPTIONAL,
  OUT EFI_SIMPLE_NETWORK_MODE          *SnpModeData    OPTIONAL
  )
/*++

Routine Description:

  This function copies the current operational settings of this EFI UDPv4 Protocol
  instance into user-supplied buffers. This function is used optionally to retrieve
  the operational mode data of underlying networks or drivers.

Arguments:

  This           - Pointer to the EFI_UDP4_PROTOCOL instance.
  Udp4ConfigData - Pointer to the buffer to receive the current configuration data.
  Ip4ModeData    - Pointer to the EFI IPv4 Protocol mode data structure.
  MnpConfigData  - Pointer to the managed network configuration data structure.
  SnpModeData    - Pointer to the simple network mode data structure.

Returns:

  EFI_SUCCESS           - The mode data was read.
  EFI_NOT_STARTED       - When Udp4ConfigData is queried, no configuration data is 
                          available because this instance has not been started.
  EFI_INVALID_PARAMETER - This is NULL.

--*/
{
  UDP4_INSTANCE_DATA  *Instance;
  EFI_IP4_PROTOCOL    *Ip;

  if (This == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  Instance = UDP4_INSTANCE_DATA_FROM_THIS (This);

  if (!Instance->Configured && (Udp4ConfigData != NULL)) {
    return EFI_NOT_STARTED;
  }

  if (Udp4ConfigData != NULL) {
    //
    // Set the Udp4ConfigData.
    //
    *Udp4ConfigData = Instance->ConfigData;
  }

  Ip = Instance->IpInfo->Ip;

  //
  // Get the underlying Ip4ModeData, MnpConfigData and SnpModeData.
  //
  return Ip->GetModeData (Ip, Ip4ModeData, MnpConfigData, SnpModeData);
}

EFI_STATUS
EFIAPI
Udp4Configure ( 
  IN EFI_UDP4_PROTOCOL     *This,
  IN EFI_UDP4_CONFIG_DATA  *UdpConfigData OPTIONAL
  )
/*++

Routine Description:

  This function is used to do the following:
    Initialize and start this instance of the EFI UDPv4 Protocol.
    Change the filtering rules and operational parameters.
    Reset this instance of the EFI UDPv4 Protocol.

Arguments:

  This          - Pointer to the EFI_UDP4_PROTOCOL instance.
  UdpConfigData - Pointer to the buffer to receive the current mode data.

Returns:

  EFI_SUCCESS           - The configuration settings were set, changed, or reset
                          successfully.
  EFI_NO_MAPPING        - When using a default address, configuration (DHCP, BOOTP,
                          RARP, etc.) is not finished yet.
  EFI_INVALID_PARAMETER - One or more following conditions are TRUE:
                            This is NULL.
                            UdpConfigData.StationAddress is not a valid unicast IPv4
                            address.
                            UdpConfigData.SubnetMask is not a valid IPv4 address mask. 
                            UdpConfigData.RemoteAddress is not a valid unicast IPv4 
                            address if it is not zero.
  EFI_ALREADY_STARTED   - The EFI UDPv4 Protocol instance is already started/configured
                          and must be stopped/reset before it can be reconfigured. Only
                          TypeOfService, TimeToLive, DoNotFragment, ReceiveTimeout, and
                          TransmitTimeout can be reconfigured without stopping the
                          current instance of the EFI UDPv4 Protocol.
  EFI_ACCESS_DENIED     - UdpConfigData.AllowDuplicatePort is FALSE and
                          UdpConfigData.StationPort is already used by other instance.
  EFI_OUT_OF_RESOURCES  - The EFI UDPv4 Protocol driver cannot allocate memory for this
                          EFI UDPv4 Protocol instance.
  EFI_DEVICE_ERROR      - An unexpected network or system error occurred and this
                          instance was not opened.

--*/
{
  EFI_STATUS           Status;
  UDP4_INSTANCE_DATA   *Instance;
  UDP4_SERVICE_DATA    *Udp4Service;
  EFI_TPL              OldTpl;
  IP4_ADDR             StationAddress;
  IP4_ADDR             SubnetMask;
  IP4_ADDR             RemoteAddress;
  EFI_IP4_CONFIG_DATA  Ip4ConfigData;

  if (This == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  Instance = UDP4_INSTANCE_DATA_FROM_THIS (This);

  if (!Instance->Configured && (UdpConfigData == NULL)) {
    return EFI_SUCCESS;
  }

  Udp4Service = Instance->Udp4Service;
  Status      = EFI_SUCCESS;

  OldTpl = NET_RAISE_TPL (NET_TPL_LOCK);

  if (UdpConfigData != NULL) {

    StationAddress = EFI_NTOHL (UdpConfigData->StationAddress);
    SubnetMask     = EFI_NTOHL (UdpConfigData->SubnetMask);
    RemoteAddress  = EFI_NTOHL (UdpConfigData->RemoteAddress);

    if (!UdpConfigData->UseDefaultAddress &&
      (!IP4_IS_VALID_NETMASK (SubnetMask) ||
      !((StationAddress == 0) || Ip4IsUnicast (StationAddress, SubnetMask)) ||
      !((RemoteAddress  == 0) || Ip4IsUnicast (RemoteAddress, 0)))) {
      //
      // Don't use default address, and subnet mask is invalid or StationAddress is not
      // a valid unicast IPv4 address or RemoteAddress is not a valid unicast IPv4 address
      // if it is not 0.
      //
      Status = EFI_INVALID_PARAMETER;
      goto ON_EXIT;
    }

    if (Instance->Configured) {
      //
      // The instance is already configured, try to do the re-configuration.
      //
      if (!Udp4IsReconfigurable (&Instance->ConfigData, UdpConfigData)) {
        //
        // If the new configuration data wants to change some unreconfigurable
        // settings, return EFI_ALREADY_STARTED.
        //
        Status = EFI_ALREADY_STARTED;
        goto ON_EXIT;
      }

      //
      // Save the reconfigurable parameters.
      //
      Instance->ConfigData.TypeOfService   = UdpConfigData->TypeOfService;
      Instance->ConfigData.TimeToLive      = UdpConfigData->TimeToLive;
      Instance->ConfigData.DoNotFragment   = UdpConfigData->DoNotFragment;
      Instance->ConfigData.ReceiveTimeout  = UdpConfigData->ReceiveTimeout;
      Instance->ConfigData.TransmitTimeout = UdpConfigData->TransmitTimeout;
    } else {
      //
      // Construct the Ip configuration data from the UdpConfigData.
      //
      Udp4BuildIp4ConfigData (UdpConfigData, &Ip4ConfigData);

      //
      // Configure the Ip instance wrapped in the IpInfo.
      //
      Status = IpIoConfigIp (Instance->IpInfo, &Ip4ConfigData);
      if (EFI_ERROR (Status)) {
        if (Status == EFI_NO_MAPPING) {
          Instance->IsNoMapping = TRUE;
        }

        goto ON_EXIT;
      }

      Instance->IsNoMapping = FALSE;

      //
      // Save the configuration data.
      //
      Instance->ConfigData                = *UdpConfigData;
      Instance->ConfigData.StationAddress = Ip4ConfigData.StationAddress;
      Instance->ConfigData.SubnetMask     = Ip4ConfigData.SubnetMask;

      //
      // Try to allocate the required port resource.
      //
      Status = Udp4Bind (&Udp4Service->ChildrenList, &Instance->ConfigData);
      if (EFI_ERROR (Status)) {
        //
        // Reset the ip instance if bind fails.
        //
        IpIoConfigIp (Instance->IpInfo, NULL);
        goto ON_EXIT;
      }

      //
      // Pre calculate the checksum for the pseudo head, ignore the UDP length first.
      //
      Instance->HeadSum = NetPseudoHeadChecksum (
                            EFI_IP4 (Instance->ConfigData.StationAddress),
                            EFI_IP4 (Instance->ConfigData.RemoteAddress),
                            EFI_IP_PROTO_UDP,
                            0
                            );

      Instance->Configured = TRUE;
    }
  } else {
    //
    // UdpConfigData is NULL, reset the instance.
    //
    Instance->Configured  = FALSE;
    Instance->IsNoMapping = FALSE;

    //
    // Reset the Ip instance wrapped in the IpInfo.
    //
    IpIoConfigIp (Instance->IpInfo, NULL);

    //
    // Cancel all the user tokens.
    //
    Udp4InstanceCancelToken (Instance, NULL);

    //
    // Remove the buffered RxData for this instance.
    //
    Udp4FlushRxData (&Instance->RcvdDgramQue);
  }

  Udp4SetVariableData (Instance->Udp4Service);

ON_EXIT:

  NET_RESTORE_TPL (OldTpl);

  return Status;
}

EFI_STATUS
EFIAPI
Udp4Groups (
  IN EFI_UDP4_PROTOCOL  *This,
  IN BOOLEAN            JoinFlag,
  IN EFI_IPv4_ADDRESS   *MulticastAddress OPTIONAL
  )
/*++

Routine Description:

  This function is used to enable and disable the multicast group filtering.

Arguments:

  This             - Pointer to the EFI_UDP4_PROTOCOL instance.
  JoinFlag         - Set to TRUE to join a multicast group. Set to FALSE to leave one
                     or all multicast groups.
  MulticastAddress - Pointer to multicast group address to join or leave.

Returns:

  EFI_SUCCESS           - The operation completed successfully.
  EFI_NOT_STARTED       - The EFI UDPv4 Protocol instance has not been started.
  EFI_NO_MAPPING        - When using a default address, configuration (DHCP, BOOTP,
                          RARP, etc.) is not finished yet.
  EFI_OUT_OF_RESOURCES  - Could not allocate resources to join the group.
  EFI_INVALID_PARAMETER - One or more of the following conditions is TRUE:
                            This is NULL.
                            JoinFlag is TRUE and MulticastAddress is NULL.
                            JoinFlag is TRUE and *MulticastAddress is not a valid 
                            multicast address.
  EFI_ALREADY_STARTED   - The group address is already in the group table (when JoinFlag
                          is TRUE).
  EFI_NOT_FOUND         - The group address is not in the group table (when JoinFlag is
                          FALSE).
  EFI_DEVICE_ERROR      - An unexpected system or network error occurred.

--*/
{
  EFI_STATUS          Status;
  UDP4_INSTANCE_DATA  *Instance;
  EFI_IP4_PROTOCOL    *Ip;
  EFI_TPL             OldTpl;

  if ((This == NULL) ||
    (JoinFlag && (MulticastAddress == NULL)) ||
    (JoinFlag && !IP4_IS_MULTICAST (EFI_NTOHL (*MulticastAddress)))) {
    return EFI_INVALID_PARAMETER;
  }

  Instance = UDP4_INSTANCE_DATA_FROM_THIS (This);

  if (Instance->IsNoMapping) {
    return EFI_NO_MAPPING;
  }

  if (!Instance->Configured) {
    return EFI_NOT_STARTED;
  }

  Ip = Instance->IpInfo->Ip;

  //
  // Invoke the Ip instance the Udp4 instance consumes to do the group operation.
  //
  Status = Ip->Groups (Ip, JoinFlag, MulticastAddress);

  if (EFI_ERROR (Status)) {
    return Status;
  }

  OldTpl = NET_RAISE_TPL (NET_TPL_LOCK);

  //
  // Keep a local copy of the configured multicast IPs because IpIo receives
  // datagrams from the 0 station address IP instance and then UDP delivers to
  // the matched instance. This copy of multicast IPs is used to avoid receive
  // the mutlicast datagrams destinated to multicast IPs the other instances configured.
  //
  if (JoinFlag) {

    NetMapInsertTail (
      &Instance->McastIps,
      (VOID *) (UINTN) EFI_IP4 (*MulticastAddress),
      NULL
      );
  } else {

    NetMapIterate (&Instance->McastIps, Udp4LeaveGroup, MulticastAddress);
  }

  NET_RESTORE_TPL (OldTpl);

  return Status;
}

EFI_STATUS
EFIAPI
Udp4Routes (
  IN EFI_UDP4_PROTOCOL  *This,
  IN BOOLEAN            DeleteRoute,
  IN EFI_IPv4_ADDRESS   *SubnetAddress,
  IN EFI_IPv4_ADDRESS   *SubnetMask,
  IN EFI_IPv4_ADDRESS   *GatewayAddress
  )
/*++

Routine Description:

  This function adds a route to or deletes a route from the routing table.

Arguments:

  This           - Pointer to the EFI_UDP4_PROTOCOL instance.
  DeleteRoute    - Set to TRUE to delete this route from the routing table. Set to
                   FALSE to add this route to the routing table.
  SubnetAddress  - The destination network address that needs to be routed.
  SubnetMask     - The subnet mask of SubnetAddress.
  GatewayAddress - The gateway IP address for this route.

Returns:

  EFI_SUCCESS           - The operation completed successfully.
  EFI_NOT_STARTED       - The EFI UDPv4 Protocol instance has not been started.
  EFI_NO_MAPPING        - When using a default address, configuration (DHCP, BOOTP,
                          RARP, etc.) is not finished yet.
  EFI_INVALID_PARAMETER - One or more of the following conditions is TRUE:
                            This is NULL.
                            SubnetAddress is NULL.
                            SubnetMask is NULL.
                            GatewayAddress is NULL.
                            SubnetAddress is not a valid subnet address.
                            SubnetMask is not a valid subnet mask.
                            GatewayAddress is not a valid unicast IP address.
  EFI_OUT_OF_RESOURCES  - Could not add the entry to the routing table.
  EFI_NOT_FOUND         - This route is not in the routing table.
  EFI_ACCESS_DENIED     - The route is already defined in the routing table.

--*/
{
  UDP4_INSTANCE_DATA  *Instance;
  EFI_IP4_PROTOCOL    *Ip;

  if (This == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  Instance = UDP4_INSTANCE_DATA_FROM_THIS (This);

  if (Instance->IsNoMapping) {
    return EFI_NO_MAPPING;
  }

  if (!Instance->Configured) {
    return EFI_NOT_STARTED;
  }

  Ip = Instance->IpInfo->Ip;

  //
  // Invode the Ip instance the Udp4 instance consumes to do the actual operation.
  //
  return Ip->Routes (Ip, DeleteRoute, SubnetAddress, SubnetMask, GatewayAddress);
}

EFI_STATUS
EFIAPI
Udp4Transmit (
  IN EFI_UDP4_PROTOCOL          *This,
  IN EFI_UDP4_COMPLETION_TOKEN  *Token
  )
/*++

Routine Description:

  This function places a sending request to this instance of the EFI UDPv4 Protocol,
  alongside the transmit data that was filled by the user.

Arguments:

  This  - Pointer to the EFI_UDP4_PROTOCOL instance.
  Token - Pointer to the completion token that will be placed into the transmit queue.

Returns:

  EFI_SUCCESS           - The data has been queued for transmission.
  EFI_NOT_STARTED       - This EFI UDPv4 Protocol instance has not been started.
  EFI_NO_MAPPING        - When using a default address, configuration (DHCP, BOOTP,
                          RARP, etc.) is not finished yet.
  EFI_INVALID_PARAMETER - One or more of the following are TRUE:
                            This is NULL.
                            Token is NULL.
                            Token.Event is NULL.
                            Token.Packet.TxData is NULL.
                            Token.Packet.TxData.FragmentCount is zero.
                            Token.Packet.TxData.DataLength is not equal to the sum of
                            fragment lengths.
                            One or more of the Token.Packet.TxData.FragmentTable[].
                            FragmentLength fields is zero.
                            One or more of the Token.Packet.TxData.FragmentTable[].
                            FragmentBuffer fields is NULL.
                            Token.Packet.TxData. GatewayAddress is not a unicast IPv4
                            address if it is not NULL.
                            One or more IPv4 addresses in Token.Packet.TxData.
                            UdpSessionData are not valid unicast IPv4 addresses if the
                            UdpSessionData is not NULL.
  EFI_ACCESS_DENIED     - The transmit completion token with the same Token.Event is
                          already in the transmit queue.
  EFI_NOT_READY         - The completion token could not be queued because the
                          transmit queue is full.
  EFI_OUT_OF_RESOURCES  - Could not queue the transmit data.
  EFI_NOT_FOUND         - There is no route to the destination network or address.
  EFI_BAD_BUFFER_SIZE   - The data length is greater than the maximum UDP packet
                          size. Or the length of the IP header + UDP header + data
                          length is greater than MTU if DoNotFragment is TRUE.

--*/
{
  EFI_STATUS              Status;
  UDP4_INSTANCE_DATA      *Instance;
  EFI_TPL                 OldTpl;
  NET_BUF                 *Packet;
  EFI_UDP4_HEADER         *Udp4Header;
  EFI_UDP4_CONFIG_DATA    *ConfigData;
  IP4_ADDR                Destination;
  EFI_UDP4_TRANSMIT_DATA  *TxData;
  EFI_UDP4_SESSION_DATA   *UdpSessionData;
  UDP4_SERVICE_DATA       *Udp4Service;
  IP_IO_OVERRIDE          Override;
  UINT16                  HeadSum;

  if ((This == NULL) || (Token == NULL)) {
    return EFI_INVALID_PARAMETER;
  }

  Instance = UDP4_INSTANCE_DATA_FROM_THIS (This);

  if (Instance->IsNoMapping) {
    return EFI_NO_MAPPING;
  }

  if (!Instance->Configured) {
    return EFI_NOT_STARTED;
  }

  //
  // Validate the Token, if the token is invalid return the error code.
  //
  Status = Udp4ValidateTxToken (Instance, Token);
  if (EFI_ERROR (Status)) {
    return Status;
  }

  OldTpl = NET_RAISE_TPL (NET_TPL_LOCK);

  if (EFI_ERROR (NetMapIterate (&Instance->TxTokens, Udp4TokenExist, Token)) ||
    EFI_ERROR (NetMapIterate (&Instance->RxTokens, Udp4TokenExist, Token))) {
    //
    // Try to find a duplicate token in the two token maps, if found, return
    // EFI_ACCESS_DENIED.
    //
    Status = EFI_ACCESS_DENIED;
    goto ON_EXIT;
  }

  TxData = Token->Packet.TxData;

  //
  // Create a net buffer to hold the user buffer and the udp header.
  //
  Packet = NetbufFromExt (
             (NET_FRAGMENT *)TxData->FragmentTable,
             TxData->FragmentCount,
             UDP4_HEADER_SIZE,
             0,
             Udp4NetVectorExtFree,
             NULL
             );
  if (Packet == NULL) {
    Status = EFI_OUT_OF_RESOURCES;
    goto ON_EXIT;
  }

  //
  // Store the IpIo in ProtoData.
  //
  Udp4Service = Instance->Udp4Service;
  *((UINTN *) &Packet->ProtoData[0]) = (UINTN) (Udp4Service->IpIo);

  Udp4Header = (EFI_UDP4_HEADER *) NetbufAllocSpace (Packet, UDP4_HEADER_SIZE, TRUE);
  ConfigData = &Instance->ConfigData;

  //
  // Fill the udp header.
  //
  Udp4Header->SrcPort      = HTONS (ConfigData->StationPort);
  Udp4Header->DstPort      = HTONS (ConfigData->RemotePort);
  Udp4Header->Length       = HTONS (Packet->TotalSize);
  Udp4Header->Checksum     = 0;

  UdpSessionData = TxData->UdpSessionData;
  Override.SourceAddress = ConfigData->StationAddress;

  if (UdpSessionData != NULL) {
    //
    // Set the SourceAddress, SrcPort and Destination according to the specified
    // UdpSessionData.
    //
    if (EFI_IP4 (UdpSessionData->SourceAddress) != 0) {
      Override.SourceAddress = UdpSessionData->SourceAddress;
    }

    if (UdpSessionData->SourcePort != 0) {
      Udp4Header->SrcPort = HTONS (UdpSessionData->SourcePort);
    }

    Destination = EFI_IP4 (UdpSessionData->DestinationAddress);

    if (UdpSessionData->DestinationPort != 0) {
      Udp4Header->DstPort = HTONS (UdpSessionData->DestinationPort);
    }

    //
    // calculate the pseudo head checksum using the overridden parameters.
    //
    HeadSum = NetPseudoHeadChecksum (
                EFI_IP4 (Override.SourceAddress),
                Destination,
                EFI_IP_PROTO_UDP,
                0
                );
  } else {
    //
    // UdpSessionData is NULL, use the address and port information previously configured.
    //
    Destination = EFI_IP4 (ConfigData->RemoteAddress);
    HeadSum     = Instance->HeadSum;
  }

  //
  // calculate the checksum.
  //
  Udp4Header->Checksum = Udp4Checksum (Packet, HeadSum);
  if (Udp4Header->Checksum == 0) {
    //
    // If the calculated checksum is 0, fill the Checksum field with all ones.
    //
    Udp4Header->Checksum = 0xffff;
  }

  //
  // Fill the IpIo Override data.
  //
  EFI_IP4 (Override.GatewayAddress) = (TxData->GatewayAddress != NULL) ?
                                      EFI_IP4 (*(TxData->GatewayAddress)) : 0;
  Override.Protocol                 = EFI_IP_PROTO_UDP;
  Override.TypeOfService            = ConfigData->TypeOfService;
  Override.TimeToLive               = ConfigData->TimeToLive;
  Override.DoNotFragment            = ConfigData->DoNotFragment;

  //
  // Save the token into the TxToken map.
  //
  Status = NetMapInsertTail (&Instance->TxTokens, Token, Packet);
  if (EFI_ERROR (Status)) {
    goto FREE_PACKET;
  }

  //
  // Send out this datagram through IpIo.
  //
  Status = IpIoSend (
             Udp4Service->IpIo,
             Packet,
             Instance->IpInfo,
             Instance,
             Token,
             Destination,
             &Override
             );
  if (EFI_ERROR (Status)) {
    //
    // Remove this token from the TxTokens.
    //
    Udp4RemoveToken (&Instance->TxTokens, Token);
  }

FREE_PACKET:

  NetbufFree (Packet);

ON_EXIT:

  NET_RESTORE_TPL (OldTpl);

  return Status;
}

EFI_STATUS
EFIAPI
Udp4Receive (
  IN EFI_UDP4_PROTOCOL          *This,
  IN EFI_UDP4_COMPLETION_TOKEN  *Token
  )
/*++

Routine Description:

  This function places a completion token into the receive packet queue. This function
  is always asynchronous.

Arguments:

  This  - Pointer to the EFI_UDP4_PROTOCOL instance.
  Token - Pointer to a token that is associated with the receive data descriptor.

Returns:

  EFI_SUCCESS           - The receive completion token is cached.
  EFI_NOT_STARTED       - This EFI UDPv4 Protocol instance has not been started.
  EFI_NO_MAPPING        - When using a default address, configuration (DHCP, BOOTP, RARP, etc.)
                          is not finished yet.
  EFI_INVALID_PARAMETER - One or more of the following conditions is TRUE:
                            This is NULL.
                            Token is NULL.
                            Token.Event is NULL.
  EFI_OUT_OF_RESOURCES  - The receive completion token could not be queued due to a lack
                          of system resources (usually memory).
  EFI_DEVICE_ERROR      - An unexpected system or network error occurred. The EFI UDPv4
                          Protocol instance has been reset to startup defaults.
  EFI_ACCESS_DENIED     - A receive completion token with the same Token.Event is already
                          in the receive queue.
  EFI_NOT_READY         - The receive request could not be queued because the receive 
                          queue is full.

--*/
{
  EFI_STATUS          Status;
  UDP4_INSTANCE_DATA  *Instance;
  EFI_TPL             OldTpl;

  if ((This == NULL) || (Token == NULL) || (Token->Event == NULL)) {
    return EFI_INVALID_PARAMETER;
  }

  Instance = UDP4_INSTANCE_DATA_FROM_THIS (This);

  if (Instance->IsNoMapping) {
    return EFI_NO_MAPPING;
  }

  if (!Instance->Configured) {
    return EFI_NOT_STARTED;
  }

  OldTpl = NET_RAISE_TPL (NET_TPL_LOCK);

  if (EFI_ERROR (NetMapIterate (&Instance->RxTokens, Udp4TokenExist, Token))||
    EFI_ERROR (NetMapIterate (&Instance->TxTokens, Udp4TokenExist, Token))) {
    //
    // Return EFI_ACCESS_DENIED if the specified token is already in the TxTokens or
    // RxTokens map.
    //
    Status = EFI_ACCESS_DENIED;
    goto ON_EXIT;
  }

  Token->Packet.RxData = NULL;

  //
  // Save the token into the RxTokens map.
  //
  Status = NetMapInsertTail (&Instance->RxTokens, Token, NULL);
  if (EFI_ERROR (Status)) {
    return EFI_NOT_READY;
  }

  //
  // If there is an icmp error, report it.
  //
  Udp4ReportIcmpError (Instance);

  //
  // Try to delivered the received datagrams.
  //
  Udp4InstanceDeliverDgram (Instance);

ON_EXIT:

  NET_RESTORE_TPL (OldTpl);

  return Status;
}

EFI_STATUS
EFIAPI
Udp4Cancel (
  IN EFI_UDP4_PROTOCOL          *This,
  IN EFI_UDP4_COMPLETION_TOKEN  *Token OPTIONAL
  )
/*++

Routine Description:

  This function is used to abort a pending transmit or receive request.

Arguments:

  This  - Pointer to the EFI_UDP4_PROTOCOL instance.
  Token - Pointer to a token that has been issued by EFI_UDP4_PROTOCOL.Transmit() or
          EFI_UDP4_PROTOCOL.Receive().

Returns:

  EFI_SUCCESS           - The asynchronous I/O request is aborted and Token.Event is 
                          signaled. When Token is NULL, all pending requests are aborted
                          and their events are signaled.
  EFI_INVALID_PARAMETER - This is NULL.
  EFI_NOT_STARTED       - This instance has not been started.
  EFI_NO_MAPPING        - When using the default address, configuration (DHCP, BOOTP,
                          RARP, etc.) is not finished yet.
  EFI_NOT_FOUND         - When Token is not NULL, the asynchronous I/O request is not
                          found in the transmit or receive queue. It is either completed
                          or not issued by Transmit() or Receive().
--*/
{
  EFI_STATUS          Status;
  UDP4_INSTANCE_DATA  *Instance;
  EFI_TPL             OldTpl;

  if (This == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  Instance = UDP4_INSTANCE_DATA_FROM_THIS (This);

  if (Instance->IsNoMapping) {
    return EFI_NO_MAPPING;
  }

  if (!Instance->Configured) {
    return EFI_NOT_STARTED;
  }

  OldTpl = NET_RAISE_TPL (NET_TPL_LOCK);

  //
  // Cancle the tokens specified by Token for this instance.
  //
  Status = Udp4InstanceCancelToken (Instance, Token);

  NET_RESTORE_TPL (OldTpl);

  return Status;
}

EFI_STATUS
EFIAPI
Udp4Poll (
  IN EFI_UDP4_PROTOCOL  *This
  )
/*++

Routine Description:

  This function can be used by network drivers and applications to increase the rate that
  data packets are moved between the communications device and the transmit/receive queues.

Argumens:

  This - Pointer to the EFI_UDP4_PROTOCOL instance.

Returns:

  EFI_SUCCESS           - Incoming or outgoing data was processed.
  EFI_INVALID_PARAMETER - This is NULL.
  EFI_DEVICE_ERROR      - An unexpected system or network error occurred.
  EFI_TIMEOUT           - Data was dropped out of the transmit and/or receive queue.

--*/
{
  UDP4_INSTANCE_DATA  *Instance;
  EFI_IP4_PROTOCOL    *Ip;

  if (This == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  Instance = UDP4_INSTANCE_DATA_FROM_THIS (This);
  Ip       = Instance->IpInfo->Ip;

  //
  // Invode the Ip instance consumed by the udp instance to do the poll operation.
  //
  return Ip->Poll (Ip);
}
